Brian There is an immense amount of literature on mixtures of distributions, generally Normal or lognormal. Unfortunately, I don't have my 1974 paper up on the...
808
Isobel Clark
drisobelclark@...
Jan 2, 2003 8:22 am
Digby The original derivation of the kriging equations does not demand any specific distribution. However, it only makes sense if the 'increments' - difference...
809
Brian R Gray
brgray@...
Jan 2, 2003 8:22 am
someone recently commented on the central limit theorem not being applicable to mixture distributions. this seems sensible but, given that that's all I've...
810
Digby Millikan
digbym@...
Jan 2, 2003 8:22 am
Brian, I am not familiar with the derivation of kriging equations, but of note I know the lognormal population does not follow the central limit theorem, and...
811
Digby Millikan
digbym@...
Jan 2, 2003 8:22 am
Francis, Have you looked at indirect lognormal corrections and affine corrections for sample sizes. Many kriging softwares use diffrent sample sizes for their...
812
Digby Millikan
digbym@...
Jan 3, 2003 8:38 am
Francis, On topic in "Lognormal-de Wijsian Geostatistics for Ore Evaluation" D.G.Krige pp5. points out that the slope of the log-probability plot provides an...
813
Digby Millikan
digbym@...
Jan 3, 2003 8:38 am
Francis, Having looked at your website further comments regarding the Australian gold mining industry that only 2 out of 35 operations acheived feasibility...
814
Digby Millikan
digbym@...
Jan 7, 2003 8:25 am
Hello, Does anyone know the first paper to discuss the covariogram or twin variogram in relation of variability of grades with distance in orebodies. Regards...
815
david boakye
david.boakye@...
Jan 7, 2003 8:25 am
Hello Does anyone know of an undeground alternative to open pit optimisation? How would you derive underground reserves from a 3-dimensional resource block...
816
Colin Daly
colin@...
Jan 7, 2003 8:25 am
Hi Digby and Isobel, Just another bit to add on the variogram. There is a large body of work that was done in the Soviet Union by Kolmogorov and his school. He...
817
Digby Millikan
digbym@...
Jan 7, 2003 8:25 am
David, If you want clarification of any of these points please do not hesiate to contact me. This is the method employed at all mines where stope design is...
818
Ruben Roa
rroa@...
Jan 7, 2003 8:25 am
Dear list members: I run into problems when creating data files with Excel 2002 for use in Variowin 2.2 Prevar2d module. Variowin says it finds an 'error while...
819
Digby Millikan
digbym@...
Jan 7, 2003 8:25 am
Hello, In regards to my last email, Isobel corrected me, I meant to say the covariance graph with distance i.e. the 'upside down variogram' not the covariogram...
820
Allison, Craig
Craig.Allison@...
Jan 7, 2003 8:25 am
Hello, I was hoping advice could be given on the following problem. We store nickel (eg 0.40 Ni %) and mill recovery (55.45%) in our mine model. From this we ...
821
Isobel Clark
drisobelclark@...
Jan 7, 2003 8:25 am
Digby There is a 96 page bibliography in the back of Cressie's book! Cressie, Noel A. C., Statistics for Spatial Data, Revised Edition, 1993, John Wiley &...
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Isobel Clark
drisobelclark@...
Jan 7, 2003 8:25 am
Colin Thanks for the info. I knew that Matheron had considerable correspodence with Gandin in Russia, who was working in meteorology but have no references to ...
823
Digby Millikan
digbym@...
Jan 7, 2003 8:25 am
Calculating averagesCraig, Don't you mean multiply Average Nickel Head grade by Average Mill recovery. Your first figure 0.3342 is correct but your figure...
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Isobel Clark
drisobelclark@...
Jan 7, 2003 8:25 am
Hi Craig The average of a product will only equal the product of the averages if the two numbers are completely independent of one another. This is exactly...
825
Digby Millikan
digbym@...
Jan 7, 2003 8:25 am
Hi David, I have designed the Gecko underground mine optimally from a block model (Gecko Mine N.T. 80 stopes). It is easier than pit optimisation because you...
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Digby Millikan
digbym@...
Jan 8, 2003 9:16 am
Hello, I was wondering if someone could give me recommendations on 'Lognormal Distributions: Theory and Applications' Edwin L. Crow for one interested in...
827
Ruben Roa
rroa@...
Jan 9, 2003 9:08 am
... file as an input for Variowin Prevar. Obviously it won't work for several reasons (a) Variowin uses the same file format as GEOEAS, a plain ASCII file, (b)...
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Pierre Goovaerts
goovaert@...
Jan 9, 2003 9:08 am
Hi Ruben, I am also working on Windows XP and have repeated your experiment. I can read the file created from Excel (option formatted text, space delimited) ...
829
Digby Millikan
digbym@...
Jan 9, 2003 9:08 am
Hello everyone, Here is a summary of my question about information on lognormal distributions in mining. ... Jeff Myers wrote: I can't help on the reference,...
830
Janusz Szmyt
jachszm@...
Jan 9, 2003 4:32 pm
Hello, My name is Janusz Szmyt. I am looking for scientists who are interested in the spatial distribution of trees within stands. Regards, Janusz [Non-text...
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Edzer J. Pebesma
e.pebesma@...
Jan 9, 2003 4:32 pm
I have a thesis in front of me called "Statistical sampling and modelling for cork oak and eucalyptus stands", written by Maria Joao Paulo. This may be ...
832
Jörgen Wallerman
Jorgen.Wallerman@...
Jan 10, 2003 8:39 am
Dear Mr Szmyt and list members, Maybe you can find what you need in any of these? Bellehumeur, C., and Legendre, P. 1998. Multiscale sources of variation in ...
833
Gregoire Dubois
aigeostats
Jan 10, 2003 10:12 am
Dear all, From now on, announcements of CONFERENCES and FREE SOFTWARE can be sent to the mailing list but only after my approval. Therefore, I will ask you to...
834
Ruben Roa
rroa@...
Jan 10, 2003 3:58 pm
Thanks to Pierre, Chris, Donald, Vassily and Tom for their suggestions in my problem with GeoEas data files under W-XP. Saving the data file in GeoEas format...
835
nicolau.barros@...
Jan 13, 2003 8:23 am
Is there any specific reason for you to use GeoEas for cross-validation? I have no experience with your kind of problem, but I'd say try using GSLIB for...
836
Digby Millikan
digbym@...
Jan 13, 2003 8:23 am
Hello, When one calculates an experimental variogram used for spatial modelling one averages the semivariogram values at each distance. This value is just an...
